Blackouts & Fertilizer Restrictions

August 6, 2018

WHY THEY EXIST AND WHAT YOU CAN DO TO KEEP YOUR LAWN HEALTHY
Depending on where you live, you may or may not be familiar with fertilizer application restriction periods, commonly referred to as “blackout periods.” While some see blackout periods as an inconvenience, the majority has come to accept them as an important step in protecting our waterways and the environment. In this article, we’ll learn the science behind why blackout periods exist. We’ll also help you comply with local and state ordinances by giving you tips that will help you keep your lawn a vibrant green during these blackout periods.

WHAT ARE BLACKOUT PERIODS?
Blackout periods are a time frame when fertilizers containing nitrogen and/or phosphorus are not permitted to be applied to turf, ornamentals, or a variety of other plants. Most blackout periods run from early June though late September and are located in tropical/subtropical climates. In the United States, the majority of blackout period laws are enforced on a county to county basis within the state of Florida. Florida blackout periods tend to correlate with the rainy season in this region. In the northeast/mid-Atlantic region, Maryland and New Jersey have their own set of blackout restrictions which run from Nov 15, through March 1. These blackout periods also correlate with this region’s rainy season.   

Fig. 1. Florida Blackout Map

A map showing the florida lawn and landscape blackout policy

Fig. 2. Golf Course Flooding

An aerial view of a golf course surrounded by trees. with heavy flooding

THE SCIENCE BEHIND BLACKOUT PERIODS
Water is the world’s most precious resource; without it, animal life suffers, and human civilization would not be possible. Blackout periods serve to protect our waterways for the greater good of our environment. In order to understand why blackout periods exist, let’s briefly brush up on our plant biology and ecology.

All plants require primary nutrients for growth and reproduction. In most cases, nitrogen and phosphorous have the greatest impact on plant growth. If either of these nutrients are lacking in the soil, plants tend to suffer. In most soils, phosphorus is already abundant, however adequate nitrogen is lacking; that’s why most fertilizers contain high concentrations of nitrogen. Using turfgrass as an example, when turf is fed an ideal amount of nitrogen under ideal conditions (perfect temperature, adequate water, adequate sunlight), turf maintains a deep green vibrancy and healthy growth rate.  

The problem begins when freshly applied fertilizer encounters a multi-day rain event. Much of this water eventually ends up in lakes or bays, and with this water comes excessive amounts of wasted fertilizer that never had a chance of being taken up by lawns and target plants. Eventually, large quantities of dissolved nitrogen and phosphorus collect in shallow lakes and bays, setting the scene for an environmental disaster caused by freshwater algae. 

Fig. 3. Freshwater Algal

A microscopic close up of green algae

Fresh water algae are a broad range of photosynthetic organisms. Some are single cellular; some are multi-cellular. Some are more like bacteria, and some are more like plants. Algae are typically divided into two large groups: blue-green algae and brown algae. No matter their classification, most algae tend to be planktonic (free-floating) and require the same primary nutrients as plants (N-P-K.)   

When algae, shallow water, sunlight, heat, and excessive fertilizer (mainly nitrogen and phosphorus) are all present, algae grow and multiply at an exponential rate, resulting in an algal bloom . This process is called eutrophication , and the effects are devastating. As the water fills with algae, animal life (such as fish, frogs, mussels, etc.) suffocate. Bottom dwelling fresh water plants die off because the sunlight becomes blocked. This results in a large body of water being depleted of oxygen. Once the algae run out of nutrients, they die off in mass quantities and sink to the bottom. This results in a population spike of bacteria, and the bacteria begin to feed on the algal remains. These same bacteria also consume large quantities of oxygen, further depleting fresh-water bodies of already scare oxygen. Once the bacteria die off, dead zones may form in lakes and bays. Dead zones are regions of water with very little oxygen that can support almost no aquatic life. Dead zones can take years, if not decades to recover from impacts of excessive fertilizer run off.

Fig. 4. Eutrophication & Dead Zones

a diagram shoiwng how the dead zone forms with algae in water

Fig. 5. Algal Bloom

A lake filled with green algae and rocks.

THE DEADLY EFFECTS OF CYANOTOXINS ON HUMAN AND ANIMAL LIFE
One of the most serious ramifications of fertilizer runoff is cyanobacteria (blue-green algae) blooms. Cyanobacteria produce highly potent toxins called cyanotoxins. This large range of compounds has been shown to harm the liver, kidneys, reproductive system, and nervous system. Some cyanotoxins are believed to be carcinogenic (numerous studies are currently under way to validate these claims). When the concentration of cyanotoxins becomes excessive in drinking water, filtering these toxins out becomes challenging. In extreme situations, municipalities will warn residents not to drink from city water supplies due to the treatment plant’s inability to filter cyanotoxins down to safe levels. 

 ALTHOUGH INCONVENIENT, SMART FERTILIZER MANAGEMENT PRACTICES BENEFIT US ALL  Whether or not an individual chooses to use fertilizer, the choices societies make regarding fertilizer use directly affect human health and the health of the environment. For all these reasons, many states have adopted regulations regarding the amount of nitrogen and phosphorus that can be applied to turf, AND when these nutrients may be applied. (For example, in Maryland, no more than 0.9 lbs N per 1000 sq ft. may be applied at any given application, and no more than 0.7 lbs N per 1000 sq ft. may be readily available nitrogen). These rules exist year-round, in addition to blackout periods. Naturally, many disagree regarding the specifics of some of these rules, but in general, as our knowledge of the science behind fertilizer run-off and eutrophication improves, regulations are re-examined and revised accordingly.

 

 WHAT CAN I DO TO KEEP MY LAWN HEALTHY DURING BLACKOUT PERIODS?

Because blackout periods typically last 3-4 months, it is imperative to make your last fertilizer application prior to the blackout period as effective as possible.


Suggestion: Before applying any fertilizers or soil amendments, check with your local, county, and state governments for ordinances regarding when and how much fertilizer you can put down in a calendar year.


There are many techniques you can use to keep your lawn green until the blackout period ends. Give these tips a try:


 1. Use more slow/controlled release nitrogen.

  • Polymer Coated Sulfur Coated urea (PCSCU, XCU, SCU, etc.) is designed to release nitrogen slowly and continuously throughout a designated time frame. Some slow/controlled release nitrogen products last 30 days; others- 90 days or more. Consider using a fertilizer blend where 75%+ of the total nitrogen in the bag is slow release. This may get you through most or all the blackout period.

 

 2. Deepen your lawn’s green color by supplementing it with an iron product.

  • Iron sulfate– this is the most common source of iron; it provides a quick greenup and is relatively inexpensive.Be careful around concrete driveways and sidewalks as this product can stain once it dissolves in water.
  • Iron sucrate– although a little more expensive than iron sulfate, this product also provides a quick greenup that can last several months. Iron sucrate is safer around concrete as it does not stain upon accidental contact.

 

 3. Add a soil amendment that conditions the soil to retain moisture and nutrients (which reduces leaching and volatilization).   AMP-XC™ Liquid Concentrate was specially formulated for blackout periods and is designed to take advantage of reduced fertilizer inputs to keep your lawn healthy and green all year long. AMP-XC (L) contains the following: 

  • Humic Substances – humic and fulvic acid condition the soil to 1.) retain soil moisture 2.) chelate micronutrients in the soil and 3.) stimulate root growth so that root systems can find more nutrients in the root zone and access more water
  • Microbial Metabolites – these amino acids, organic acids, protein hydrolysates and other organic compounds provide turf all the building blocks it needs to accelerate its growth and metabolism
  • Chelated Iron – 100% soluble EDTA iron gets into plant roots more efficiently than any other form of iron; great for maximum greening during blackout periods 

 

For professional fertilizers, humic and AMP-XC™ enriched products available, please visit TurfCare’s online Product Catalog.
  
 For green industry professionals or others interested in ordering Turfcare products, please contact our Customer Service to find a distributor near you.

Resources:
http://mda.maryland.gov/SiteAssets/Pages/fertilizer/TT119.pdf
https://www.epa.gov/nutrient-policy-data/cyanobacteriacyanotoxins
https://oceanservice.noaa.gov/facts/eutrophication.html
https://www.nj.gov/dep/healthylawnshealthywater/
https://www.cga.ct.gov/2012/rpt/2012-R-0076.htm
http://mda.maryland.gov/Pages/fertilizer.aspx
https://www.volusia.org/services/community-services/extension/horticulture/fertilizer-faqs.stml

Pictures:
Blackout Periods 01 - Eutrophication & Dead Zones http://slideplayer.com/slide/1660466/7/images/25/Eutrophication+and+Dead+Zones.jpg
Blackout Periods 02 - Algal Bloom http://www.miseagrant.umich.edu/wp-content/blogs.dir/1/files/hab/hab-dsc_5400.jpg
Blackout Periods 03 - Florida Blackout Map gcmonline.com/news/adopting-seasonal-fertilizer-blackout-periods (note, this link is dead)
Blackout Periods 04 – Eutrophication in Lake Erie http://ecofore.org/wp-content/uploads/2014/01/lake-erie-is-dead.jpg
Blackout Periods 05 – Algal Bloom 2 http://blogs.edf.org/growingreturns/files/2015/10/Ohio-Wetlands-Association.jpg
Blackout Periods 06 – Algal Bloom 3 https://toxics.usgs.gov/photo_gallery/photos/emer_cont/cyanobac/AlgaeBloomSign_MarionReservoirKS_003_l.jpg
Blackout Periods 07 - Impact of Cyanotoxins http://www.cleanwateraction.org/sites/default/files/The%20Health%20Impacts%20of%20Cyanotoxins.jpg
Blackout Periods 08 - Golf Course Flooding http://www.calgaryherald.com/news/alberta/cms/binary/10042271.jpg?size=640x420
Blackout Periods 09 - Freshwater Algae http://4.bp.blogspot.com/-lGEkrjygcpM/VRM-QOVz3gI/AAAAAAAADZ8/VDu3oGr9kbk/s1600/freshwater-algae.jpg

The TURFReport Highlights:

Additional Articles and Insights

January 30, 2026
White Plains, NY – January 30, 2026 – Interoceanic Corporation (“IOC”) announced today that its affiliate Spring Valley USA (Spring Valley) , has acquired the blending and packaging assets and business of Turf Care Supply, LLC, a leading manufacturer and blender of turf and ornamental fertilizers as well as ice melt. The combination of Spring Valley and Turf Care Supply’s blending business, forms one of the largest independent lawn and garden fertilizer platforms in North America. The integrated business will have approximately 250 employees and will operate eight manufacturing and blending facilities across seven states, enabling coast-to-coast coverage of customers. By uniting two highly complementary companies, this acquisition creates a world-class turf & ornamental supply company positioned to deliver enhanced value to both professional and retail customers. “This acquisition is a transformative step for our organization,” said Elio Mazzella , President of IOC and Spring Valley. “By bringing Turf Care Supply into the IOC family, we are significantly expanding our reach and capabilities in serving the lawn and garden industry. The combined company will have an unrivaled production footprint and product portfolio, which means we can offer our customers faster service, greater efficiency, and innovative solutions on a national scale. Our goal is to build a world-class platform that blends the strengths of both businesses – the supply chain efficiencies of the combined business and the family-business values – will drive growth for our customers and vendor partners.” With the closing of the transaction, Turf Care Supply, LLC will be renamed Allied Nutrients and continue to manufacture leading enhanced efficiency fertilizers (“EEF”) out of its Martins Ferry, Ohio facility. Mark Mangan, President of Allied Nutrients, commented, “we want to thank our long-time employees that will be joining the IOC family and wish them well. We have known the IOC team for many years and believe this will be a great home. At the same time, we are excited for our remaining employees as we focus our resources and efforts on providing the best EEF solutions to the turf and ornamental market.” With this acquisition, the combined company now operates manufacturing facilities in Wisconsin, Ohio, Texas, Florida, Massachusetts, Tennessee, and Oklahoma, giving it the ability to blend and package fertilizer products and ice melt closer to customers in every major region. Turf Care Supply’s sites in Hatfield (MA), Sebring (FL), Cleveland (TN), and Catoosa (OK) will join Spring Valley’s existing plants in Jackson (WI), Fostoria (OH), Greenville (TX), and Longwood (FL). This expanded footprint significantly reduces transit times and enhances supply reliability for our customers. Maintaining strong customer relationships during and after the integration is a top priority. “All of our customers will continue to receive the outstanding service and product quality they expect, now with the added benefit of a truly national production network,” Mazzella added. Each major customer will be supported by an expanded team dedicated to ensuring a seamless transition and ongoing success. Strategically, the merger of Spring Valley and Turf Care Supply unlocks significant commercial synergies that will benefit both our customers and vendor partners. Together, the company will offer the most comprehensive product portfolio in the industry. “This combination is about building a platform that is perfectly suited to support our customers growth,” said Mazzella. “By combining our R&D and product development efforts, we intend to bring new, high-value solutions to market that neither company could have achieved alone.” The integration of the two businesses is already underway, with a focus on maintaining operational continuity and exceptional customer service throughout the spring season. The company also emphasized that all Turf Care Supply employees are being welcomed into the organization, and that the combined workforce will play a crucial role in driving the business forward. “This is an exciting moment for all of us. By uniting two great teams, we’re creating a stronger company with a shared commitment to our customers’ and vendors success, ” Mazzella noted. About Interoceanic Corporation (IOC): Based in White Plains, NY, IOC is a diversified family-owned company specializing in the production, marketing, and distribution of fertilizer and industrial chemical products. Other notable affiliates of IOC are PCI Nitrogen, Columbia River Nitrogen and EM² Enterprises. With this transaction, the group of businesses consist of over 600 employees. IOC’s family values, entrepreneurial spirit, and supply chain expertise have driven its growth from a regional fertilizer distributor into an international platform that provides reliable, high-quality products. About Allied Nutrients: Based in Brunswick, OH, Allied Nutrients specializes in providing enhanced efficiency fertilizers that support turfgrass and ornamental plant health. Through world-class manufacturing and research and development, the company offers a comprehensive portfolio of products, including SCU, PCU, PCSCU, reacted slow-release nitrogen, and urease inhibitors. These solutions are marketed under leading brands, such as XCU, TTRU, UFLEXX, UMAXX, Nutralene, and Nitroform. 
The hidden cost of filler: how to maximize your fertilizer ROI. Shows hand holding filler .
January 22, 2026
Want to maximize your ROI and turf health? Ditch the filler and replace your blends with Enhanced Efficiency Fertilizers (EEFs), Micro packs, Soil Amendments, or organic materials. These alternatives can reduce your seasonal application of bags, reduce overall material cost and deliver better results!
A large fertilizer manufacturing facility
April 18, 2025
Turf Care Supply, LLC, a portfolio company of Platte River Equity, has officially acquired Beaty Fertilizer, the industry respected Tennessee-based manufacturer and blender of custom granular and liquid fertilizers, as well as combination products. This strategic move expands Turf Care’s manufacturing footprint, adds new product capabilities, and enhances overall production capacity.
grubs on dirt
April 18, 2025
Root out Grubs, Before they Attack Yours!
October 9, 2024
Platte River Equity Portfolio Company Turf Care Supply, LLC Acquires Agri-Nutrients, Inc.
October 4, 2024
Dear Valued Industry Partners and Customers, We are pleased to announce that Turf Care Supply, LLC has acquired Agri-Nutrients, Inc. (October 1, 2024) a respected manufacturer in the turf and ornamental fertilizer industry. This acquisition marks a significant step forward in our commitment to providing you with an expanded range of innovative products, services, and industry expertise, all designed to support your business’s continued growth and success. As a valued partner or customer, you will benefit from enhanced service capabilities and an extended geographic reach, thanks to Agri-Nutrients, Inc.’s strategic facility located in the Port of Catoosa, Oklahoma. With this established presence in the Southwest and Western markets, Turf Care Supply, LLC’s expanded operational footprint will allow us to serve a broader region with greater efficiency, delivering even stronger support to help drive your business forward. We are dedicated to ensuring a seamless transition while maintaining the high standards of service you expect. If you have any questions or would like to explore how this new location can enhance your operations, please feel free to contact your account manager or our customer service team. Thank you for your continued trust in Turf Care Supply, LLC . We look forward to partnering with you as we grow together and continue supporting your success. Sincerely, Mark ManganPresidentTurf Care Supply, LLC
A forklift is sitting in a garage next to another forklift.
September 28, 2023
With a focus on providing sustainable manufacturing and reducing carbon emissions, Turf Care Supply has embraced the electric power market with the latest mobile equipment upgrades. Completed in June 2023, TCS received all deliveries of electric forklifts to all three manufacturing facilities, including Hatfield, MA, Martins Ferry, OH and Sebring, FL.
A person is holding a safety data sheet in front of bottles
July 19, 2023
When handling fertilizers and pesticide it is important to follow suggested guidelines and prioritize safety to protect yourself, others, and reduce environmental impact. Here are some general measures to follow: 1.Read and Follow Instructions: Carefully read and understand the product labels, safety data sheets (SDS), and any accompanying instructions provided by the manufacturer. Follow all recommended guidelines, precautions, and application rates.
A tur care advertisement for fertilizer application tips
June 22, 2023
It’s common knowledge that applying too much fertilizer containing high percentages of readily available nitrogen and water soluble nutrients can result in burn damage to plants, but did you know that damage can still occur even if your application rate is correct? Applying the right product at the right rate, but at the WRONG time can have disastrous consequences.
Show More
January 30, 2026
White Plains, NY – January 30, 2026 – Interoceanic Corporation (“IOC”) announced today that its affiliate Spring Valley USA (Spring Valley) , has acquired the blending and packaging assets and business of Turf Care Supply, LLC, a leading manufacturer and blender of turf and ornamental fertilizers as well as ice melt. The combination of Spring Valley and Turf Care Supply’s blending business, forms one of the largest independent lawn and garden fertilizer platforms in North America. The integrated business will have approximately 250 employees and will operate eight manufacturing and blending facilities across seven states, enabling coast-to-coast coverage of customers. By uniting two highly complementary companies, this acquisition creates a world-class turf & ornamental supply company positioned to deliver enhanced value to both professional and retail customers. “This acquisition is a transformative step for our organization,” said Elio Mazzella , President of IOC and Spring Valley. “By bringing Turf Care Supply into the IOC family, we are significantly expanding our reach and capabilities in serving the lawn and garden industry. The combined company will have an unrivaled production footprint and product portfolio, which means we can offer our customers faster service, greater efficiency, and innovative solutions on a national scale. Our goal is to build a world-class platform that blends the strengths of both businesses – the supply chain efficiencies of the combined business and the family-business values – will drive growth for our customers and vendor partners.” With the closing of the transaction, Turf Care Supply, LLC will be renamed Allied Nutrients and continue to manufacture leading enhanced efficiency fertilizers (“EEF”) out of its Martins Ferry, Ohio facility. Mark Mangan, President of Allied Nutrients, commented, “we want to thank our long-time employees that will be joining the IOC family and wish them well. We have known the IOC team for many years and believe this will be a great home. At the same time, we are excited for our remaining employees as we focus our resources and efforts on providing the best EEF solutions to the turf and ornamental market.” With this acquisition, the combined company now operates manufacturing facilities in Wisconsin, Ohio, Texas, Florida, Massachusetts, Tennessee, and Oklahoma, giving it the ability to blend and package fertilizer products and ice melt closer to customers in every major region. Turf Care Supply’s sites in Hatfield (MA), Sebring (FL), Cleveland (TN), and Catoosa (OK) will join Spring Valley’s existing plants in Jackson (WI), Fostoria (OH), Greenville (TX), and Longwood (FL). This expanded footprint significantly reduces transit times and enhances supply reliability for our customers. Maintaining strong customer relationships during and after the integration is a top priority. “All of our customers will continue to receive the outstanding service and product quality they expect, now with the added benefit of a truly national production network,” Mazzella added. Each major customer will be supported by an expanded team dedicated to ensuring a seamless transition and ongoing success. Strategically, the merger of Spring Valley and Turf Care Supply unlocks significant commercial synergies that will benefit both our customers and vendor partners. Together, the company will offer the most comprehensive product portfolio in the industry. “This combination is about building a platform that is perfectly suited to support our customers growth,” said Mazzella. “By combining our R&D and product development efforts, we intend to bring new, high-value solutions to market that neither company could have achieved alone.” The integration of the two businesses is already underway, with a focus on maintaining operational continuity and exceptional customer service throughout the spring season. The company also emphasized that all Turf Care Supply employees are being welcomed into the organization, and that the combined workforce will play a crucial role in driving the business forward. “This is an exciting moment for all of us. By uniting two great teams, we’re creating a stronger company with a shared commitment to our customers’ and vendors success, ” Mazzella noted. About Interoceanic Corporation (IOC): Based in White Plains, NY, IOC is a diversified family-owned company specializing in the production, marketing, and distribution of fertilizer and industrial chemical products. Other notable affiliates of IOC are PCI Nitrogen, Columbia River Nitrogen and EM² Enterprises. With this transaction, the group of businesses consist of over 600 employees. IOC’s family values, entrepreneurial spirit, and supply chain expertise have driven its growth from a regional fertilizer distributor into an international platform that provides reliable, high-quality products. About Allied Nutrients: Based in Brunswick, OH, Allied Nutrients specializes in providing enhanced efficiency fertilizers that support turfgrass and ornamental plant health. Through world-class manufacturing and research and development, the company offers a comprehensive portfolio of products, including SCU, PCU, PCSCU, reacted slow-release nitrogen, and urease inhibitors. These solutions are marketed under leading brands, such as XCU, TTRU, UFLEXX, UMAXX, Nutralene, and Nitroform. 
The hidden cost of filler: how to maximize your fertilizer ROI. Shows hand holding filler .
January 22, 2026
Want to maximize your ROI and turf health? Ditch the filler and replace your blends with Enhanced Efficiency Fertilizers (EEFs), Micro packs, Soil Amendments, or organic materials. These alternatives can reduce your seasonal application of bags, reduce overall material cost and deliver better results!
A large fertilizer manufacturing facility
April 18, 2025
Turf Care Supply, LLC, a portfolio company of Platte River Equity, has officially acquired Beaty Fertilizer, the industry respected Tennessee-based manufacturer and blender of custom granular and liquid fertilizers, as well as combination products. This strategic move expands Turf Care’s manufacturing footprint, adds new product capabilities, and enhances overall production capacity.
grubs on dirt
April 18, 2025
Root out Grubs, Before they Attack Yours!
October 9, 2024
Platte River Equity Portfolio Company Turf Care Supply, LLC Acquires Agri-Nutrients, Inc.
October 4, 2024
Dear Valued Industry Partners and Customers, We are pleased to announce that Turf Care Supply, LLC has acquired Agri-Nutrients, Inc. (October 1, 2024) a respected manufacturer in the turf and ornamental fertilizer industry. This acquisition marks a significant step forward in our commitment to providing you with an expanded range of innovative products, services, and industry expertise, all designed to support your business’s continued growth and success. As a valued partner or customer, you will benefit from enhanced service capabilities and an extended geographic reach, thanks to Agri-Nutrients, Inc.’s strategic facility located in the Port of Catoosa, Oklahoma. With this established presence in the Southwest and Western markets, Turf Care Supply, LLC’s expanded operational footprint will allow us to serve a broader region with greater efficiency, delivering even stronger support to help drive your business forward. We are dedicated to ensuring a seamless transition while maintaining the high standards of service you expect. If you have any questions or would like to explore how this new location can enhance your operations, please feel free to contact your account manager or our customer service team. Thank you for your continued trust in Turf Care Supply, LLC . We look forward to partnering with you as we grow together and continue supporting your success. Sincerely, Mark ManganPresidentTurf Care Supply, LLC
A forklift is sitting in a garage next to another forklift.
September 28, 2023
With a focus on providing sustainable manufacturing and reducing carbon emissions, Turf Care Supply has embraced the electric power market with the latest mobile equipment upgrades. Completed in June 2023, TCS received all deliveries of electric forklifts to all three manufacturing facilities, including Hatfield, MA, Martins Ferry, OH and Sebring, FL.
A person is holding a safety data sheet in front of bottles
July 19, 2023
When handling fertilizers and pesticide it is important to follow suggested guidelines and prioritize safety to protect yourself, others, and reduce environmental impact. Here are some general measures to follow: 1.Read and Follow Instructions: Carefully read and understand the product labels, safety data sheets (SDS), and any accompanying instructions provided by the manufacturer. Follow all recommended guidelines, precautions, and application rates.
Show More